Film feed for wrapping machines



March 29, 1966 c. M. RossER FILM FEED FOR WRAPPING MACHINES Filed Dec. 13, 1962 United States Patent 3,242,639 FILM FEED FOR WRAPPING MACHINES Charles M. Rosser, Wallingford, Pa., assignor, by mesne assignments, to FMC Corporation, San 305e, Cahf., a corporation of Delaware Filed Dec. 13, 1962, Ser. No. 244,387 2 Claims. (Cl. 53-389) This invention relates to wrapping machines of the type employed for wrapping bread, cakes or the like and more particularly to those types of machines wherein the wrapping material is push fed into position for wrapping individual articles. In its more particular aspects, the invention relates to an improved push-feed wrapping machine adapted to employ thin films as the wrapping material.

Cellulosic and resinous plastic films are commonly employed for wrapping bread, cakes and the like in automatic machines operating at relatively high speeds. In the so-called push-feed machines, the film is generally supplied from a roll or other indefinitely elongated supply and the end of the film is periodically pushed from a first position where the film has previously been severed to a remotely located catching device or station where the end of the film is grasped preparatory to wrapping an individual article such as a loaf of bread or a cake. In some machines, the film moves more or less horizontally over a table or other non-confining support as it approaches the catching device. An example of such a machine is shown and described in US. Patent No. 2,310,719 to Tuthill et al. and it is toward the improvement of such machines that the present invention is directed.

In order for the film to be successfully pushed into wrapping position, it is necessary for it to have a certain degree of stiffness or rigidity so as to prevent it from curling as the end thereof meets with air resistance. It is also important that the film be cleanly cut so as to avoid curling the end before the pushing action takes place. Ordinary commercial grades of coated regenerated cellulose films having a thickness of the order of approximately one mil or more have sufficient stiffness to be pushed into wrapping position and are capable of being cut cleanly. Recently, however, thinner regenerated cellulose films seven or eight tenths of a mil thick have been offered and these are considerably less rigid, rendering them difiicult to push into wrapping position and difficult to cut. The present invention provides means for increasing the stiifness of the end of the film whereby the pushing of the thin film into wrapping position is facilitated and further the invention provides means for improving the cutting of the film.

It is an object of the invention to provide in a pushfeed wrapping machine, means for stiffening the end portion of a thin wrapping film prior to pushing the film into wrapping position, whereby the desired movement of the film is facilitated.

A further object of the invention is to provide in a wrapping machine, improved means for cutting thin films of wrapping material.

Other objects, features and advantages of the invention as well as the means for attaining the same will become apparent as the description of a preferred embodiment proceeds.

Referring now to the drawing:

FIG. 1 is a side elevational view of a portion of a wrapping machine embodying the invention; and

FIG. 2 is a perspective view on an enlarged scale of a portion of the film gripping and crimping elements of the invention and showing the association of such elements with the film cutting members.

The machine partially shown in the drawing, except for 3,242,639 Patented Mar. 29, 1956 the feature of the present invention, may be constructed as described in the above-mentioned Patent No. 2,310,719 and reference is hereby made to said patent for a full explanation of the machine, only so much thereof being shown in the present drawing as is necessary to an understanding of the present invention.

The supply of film is indicated at 10 and the film 11 is lead from the supply over a feeding drum 12 cooperating with which are a plurality of idler feed rolls 13. A plurality of belts 14 are trained about drum 12 and a plurality of small idler rollers 15. A plurality of belts 16 are trained about rollers 13 and otherrollers 17 located above rollers 15. Belts 14 and 16 help to guide and feed the film which passes therebetween to a cutting station generally indicated at 18. Rollers 13 are carried by pivotally mounted cranks 19 and are urged toward engagement with the drum 12 by one or more springs 20 working against said cranks. A cross shaft 21 carries eccentrics 22 whereby when said cross shaft is manually operated in a suitable manner the eccentrics will rock cranks 19 so as to elevate rollers 13 away from drum 12 to facilitate the initial introduction of the film into the film feeding mechanism. In a manner presently to be explained, the film is push-fed from cutting station 18 to a remotely located film-end catching station comprising a pair of rollers 23 and 24 which are spaced apart at the time the film is fed thereto and which then close to grip the film as explained in the above-mentioned patent.

An elevator generally indicated at 25 is pivotally connected at 26 to one end of an operating member 27 the other end of which is pivotally mounted at 28 on the machine framework. Elevator operating member 27 carries intermediate its ends a cam-following roller 29 which rides the surface of a cam 30 secured on a cross shaft 31. Somewhat over half the periphery of cam 30 is concentric with shaft 31 and in FIG. 1 roller 29 is resting on the concentric portion of said cam and elevator 25 is positioned as shown in full lines. As explained in the above referred to patent, from time to time shaft 31 is caused to rotate clockwise through a single revolution and during this revolution the low portion of cam 30 passes beneath roller 29 so as to permit elevator operating arm 27 and the elevator 25 to move downward to the position shown in dotted lines. The elevator comprises a supporting member 32 secured to which are a pair of vertically spaced plates 33 and 34 and secured to upper plate 34 is a table 35. When the elevator moves downward to the dotted-line position, the surface of table 35 becomes aligned with a conveyor 36 and said conveyor discharges onto the table an article to be wrapped such as a loaf of bread 37. So that the table 35 will tilt into alignment with conveyor 36 as said elevator moves to its lower position, a downwardly projecting arm 38 is provided on plate 33 and the lower end of said arm is pivotally connected at 39 to one end of link 40, the other end of which is pivotally connected at 28 to the machine framework. As explained in the above-mentioned patent and as will be further alluded to hereinafter, the wrapping operation begins as the bread moves from the conveyor onto table 35.

The film cutter, located at the cutting station 18, comprises a fixed upper blade 41 secured to a brace member 42 and a relatively movable lower blade 43 secured to an operating member 44. Operating member 44 is pivotally connected at 45 to the machine framework and comprises a downwardly directed pair of arms, one of which is indicated at 46 and between which is retatably mounted a cam following roller 47 which rests upon the surface of a cam 48 secured to cross shaft 31. In the main, the surface of cam 48 is concentric with shaft 31, but said cam has a protuberance 49 which becomes aligned with roller 47 at one point in the aforementioned revolution of shaft 31 so as to raise blade operating member 44 and move the cutting edge of blade 43 across the cutting edge of blade 41. The cutting edge of blade 43 is sloped so as to provide a scissors-like cutting action between blade 43 and blade 41.

Resiliently connected to blade 43 is a film gripping and crimping member 50 having a wide upper face provided with a series of serrations 51 extending in a direction longitudinally of wrapping film 11. As shown in FIG. 2, member 50 is provided with a plurality of screws or bolts 52, only one of which is shown, which extend through elongated slots 53 provided in blade 43. A washer 54 or the like may be provided between the head of bolt 52 and the side of the blade. A spring 55 mounted in slot 53 urges bolt 52 and the member 50 to which it is connected upwardly and for a reason presently to be explained a thin shim 56 is provided between the cutting face of blade 43 and the adjacent face of member 50. Brace member 42 to which stationary blade 41 is connected extends slightly below the cutting edge of said blade and its bottom face is provided with a series of serrations 57 extending in a direction longitudinally of film 11. As the lower blade 42 moves up as aforesaid to cut the film in cooperation with blade 41, member 50 moves up with it due to the action of spring 55 and grips the film between it and the lower face of member 42 prior to the actual engagement of blade 43 with blade 41, springs 55 permitting the lower blade 43 to continue its upward movement after member 59 has been arrested. The serrations 51 of member 50 are arranged to nestingly cooperate with serrations 57 of member 42 so that when the film is pinched therebetween it is crimped as indicated at 58. The crimps 58 serve to considerably stiffen the film immediately adjacent the line where the film is cut by blades 41 and 43. Of course, instead of running longitudinally of the film, the serrations of members 42 and 50 may be arranged so as to produce any desired pattern on the film, for example a diamond pattern. The important feature of the invention is that the film is crimped in a manner to impart stiifness.

As best shown in FIG. 2, blade 41 is recessed into member 42 so that the cutting edge of the blade lies closely adjacent the side face of said member. Shim 56 is of such thickness that with blade 43 in cutting engagement wit-h blade 41, the gripping faces of mem bers 42 and 50 will be in contact over their entire area. By recessing blade 41 into member 42, the film is cut very closely adjacent the point where the film is gripped. Instead of shim 56, member 50 may be provided with an offset face so as to space serrations 51 slightly out of vertical alignment with the cutting edge of blade 43.

Very thin film is difficult to cut cleanly and as the cutting edge of blade 43 moves past the cutting edge of blade 41 there is a tendency, particularly unless the blades are exceedingly sharp, for the film to be pulled forward from the supply and curl up against the face of blade 41, that is, to move between the faces of blades 41 and 43 rather than being cut. Gripping members 42 and 50 by grasping the film firmly at the time of the cutting operation prevent the film from being pulled from the supply and thereby serve to facilitate the cutting operation.

After the film has been cut at the cutting station 18, the newly formed crimped end of the film is shoved or pushed, as will presently be described, from the cutting station to the remotely located catching station comprised of the rollers 23 and 24. In moving from cutting station 18 to the gripping rollers 23 and 24, the film passes through the tunnel provided by elevator plate members 33 and 34. Plates 33 and- 34 are spaced rather widely apart, at least in relation to the thickness of the film, and as the end of the film meets with air resistance during the passage through the tunnel it has a strong tendency to curl and become jammed in the tunnel. As previously mentioned, heavy grades of film can be successfully shoved through the space between plates 33 and 34 but because of a lack of stiffness, relatively thin films are much more subjected to jamming unless some means is provided for stiffening them or at least for stiffening the leading end. Not only must the film move freely between plates 33 and 34 but the end thereof must, of course, pass between rollers 23 and 24 and if the film should become curled due to poor cutting or due to air resistance there is a strong likelihood that the end would not pass properly into the area between rollers 23 and 24.

The film is cut at cutting station 18 shortly after the leading end thereof is gripped by rollers 23 and 24, and elevator 25 then begins its downward movement from the full-time position to the dotted-line position and as the elevator moves down the film is pulled part way through the space between plates 33 and 34 so as to extend as shown in chain dotted lines into the path of movement of the article 37 as it moves from conveyor 36 onto the elevator table 35. When the article becomes fully positioned on table 35 the film extends around one side of the article and a portion of the bottom thereof, the movement of the article onto the table serving to pull the free end of the film out from between plates 33 and 34. Elevator 25 is then moved back to the full-line position and the wrapping of the article is completed as explained in Patent No. 2,310,719.

For push feeding the film from cutting station 18 to the catching station comprised of rollers 23 and 24, the

following mechanism is provided. Feeding drum 12 is mounted on a shaft 59 and connected to said drum by a one-way clutch is a pinion 60 with which is meshed a curved rack 61. Rack 61 is carried by an arm 62 pivotally mounted on the framework at 63. A link 64 connects arm 62 with a link 65 pivotally mounted at one end at 66 on the framework and pivotally connected at the other end to one end of a link 67, the opposite end of which is pivotally connected to a crank arm 68 secured to cross shaft 31. As shaft 31 begins its clockwise revolution as previously described, rack 61 moves upward through the aforesaid system of linkages so as to rotate pinion 60 in a counter-clockwise direction but because of the one-way or over-running clutch between said pinion and said drum 12 this movement does not affect the drum. During the later part of the revolution of shaft 31 racks 61 moves down so as to rotate pinion 60 and feeding drum 12 in a clockwise direction. Drum 12 with its cooperating belts 14 and 16 is thereupon efiective to push the crimped end of the film from the cutting station 18 to the remotely located catching station comprised of rollers 23 and 24.

Having thus described the invention, what is claimed 1. In a wrapping machine, means for drawing a thin film from a roll and periodically push-feeding the end thereof substantially horizontally from a first position through guide means spaced from the opposite faces of the film to a remotely located film end catching station, cutting means located adjacent said first position for cutting the film after the end of the film has been fed to the catching station thereby providing a new leading end for the film extending to the supply, said cutting means comprising a fixed blade and a relatively movable blade, a first film crimping member juxtaposed the non-cutting face of one of said blades, 21 second film crimping member juxtaposed the cutting face of the other of'said blades, means resiliently connecting said second film crimping member to said other of said blades for movement relative thereto, and means for moving said relatively movable blade in cutting relationship with said fixed blade, said crimping members engaging the film prior to the engagement, of the cutting edges of said blades so as to grip and crimp the film prior to cutting.

2. In a wrapping machine, means for drawing a thin film from a roll and periodically push-feeding the end thereof substantially horizontally from a first position through guide means spaced from the opposite faces of the film to a remotely located film end catching station, cutting means located adjacent said first position for cutting the film after the end of the film has been fed to the catching station thereby providing a new leading end for the film, said cutting means comprising a fixed upper blade and a relatively movable lower blade, a first film crimping member juxtaposed the non-cutting face of said upper blade, a second film crimping member juxtaposed the cutting face of said lower blade, means resiliently connecting said second film crimping member to said lower blade for movement therewith and relative thereto, and means for moving said lower blade in cutting relationship with said upper blade, said crimping members engaging the film prior to the engagement of the cutting edges of said blades so as to grip and crimp the film prior to cutting.

References Cited by the Examiner UNITED STATES PATENTS 2,350,244 5/1944 Malhiot 53-389 XR 2,961,814 11/1960 Redmond et al. 53389 XR 10 3,055,154 9/1962 Markley eta-l1 53 1s2 FOREIGN PATENTS 199,507 6/1923 Great Britain.

5 TRAVIS s. McGEI-IEE, Primary Examiner.

A. E. FOURNIER, Assistant Examiner. 

1. IN A WRAPPING MACHINE, MEANS FOR DRAWING A THIN FILM FROM A ROLL AND PERIODICALLY PUSH-FEEDING THE END THEREOF SUBSTANTIALLY HORIZONTALLY FROM A FIRST POSITION THROUGH GUIDE MEANS SPACED FROM THE OPPOSITE FACES OF THE FILM TO A REMOTELY LOCATED FILM END CATCHING STATION, CUTTING MEANS LOCATED ADJACENT SAID FIRST POSITION FOR CUTTING THE FILM AFTER THE END OF THE FILM HAS BEEN FED TO THE CATCHING STATION THEREBY PROVIDING A NEW LEADING END FOR THE FILM EXTENDING TO THE SUPPLY, SAID CUTTING MEANS COMPRISING A FIXED BLADE AND A RELATIVELY MOVABLE BLADE, A FIRST FILM CRIMPING MEMBER JUXTAPOSED THE NON-CUTTING FACE OF ONE OF SAID BLADES, A SECOND FILM CRIMPING MEMBER JUXTAPOSED THE CUTTING FACE OF THE OTHER OF SAID BLADES, MEANS RESILIENTLY CONNECTING SAID SECOND FILM CRIMPING MEMBER TO SAID OTHER OF SAID BLADES FOR MOVEMENT RELATIVE THERETO, AND MEANS FOR MOVING AND RELATIVELY MOVABLE BLADE IN CUTTING RELTIONSHIP WITH SAID FIXED BLADE, SAID CRIMPING MEMBERS ENGAGING THE FILM PRIOR TO THE ENGAGEMENT OF THE CUTTING EDGES OF SAID BLADES SO AS TO GRIP AND CRIMP THE FILM PRIOR TO CUTTING. 